Study On Two-stage Iron And Magnesium Desulfurization Combined Process And Performance Of The Byproduct PFMS

This paper dealt with one two-stage flue gas desulfurization process, which was designed to reduce packed height of the absorbing tower and the dosage of oxidant. The combined process included iron-desulfurization stage and magnesia-desulfurization stage. The continuous experiments indicated that high desulfurization efficiencies were achieved and the byproducts of Mg-Fe composite flocculants (i.e. the serous fluid mixture of two stages) were acquired. Furthermore, the flocculation performances of PFMS and PFS were investigated.For the iron-stage of combined process, packing height and the absorption liquid temperature were intended to0.2m and15℃, respectively. The optimum inlet concentrations range of sulfur dioxide and liquid/gas ratio on desulfurization efficiencies were also investigated.The determination inlet concentrations range of sulfur dioxide and liquid/gas ratio on desulfurization efficiencies could contribute to the performances of the magnesium-stage of combined process, such as the desulfurization efficiencies and liquid-gas ratio.Selecting the right conditions for the continuous operations of the combined process, the desulfurization efficiency more than91%and PFMS were obtained. Compared with the iron desulfurization process, the packing height was reduced by0.8m to achieving similar desulfurization rate. Theoretical calculations showed that the cost of raw materials to produce1ton of polymerization by-product of Mg-Fe composite flocculant PFMS was reduced by20.85yuan RMB and that of oxidants was reduced by16.96yuan RMB.The kaolin simulated turbidity wastewater, direct fast black G simulated dyeing waste water wastewater and coking wastewater were used to evaluate the performances of PFMS, PFS and industrial solid PFS flocculation, respectively. The experimental results showed that the turbidity and color removal efficiency by the desulphurisation products PFMS were the same as the byproduct PFS and industrial PFS. And in alkaline conditions, the COD removal efficiencies by PFMS were higher than PFS and industrial PFS.